TVIS Remove or not to remove?

Not planning to go over 450hp.... so you have 264 or larger aftermarket camshafts, turbo, 1200cc or larger injectors, running e85, crw/ats cv and many other mods running over 24psi and at the limits of stock intake manifold and stock exhaust manifold.
IMO. Remove TVIS! Yes remove TVIS!
TVIS is great for stock. Dyno have shown it can pick up 100rpm or so in spool. However in higher boost it becomes a restriction. But that’s not the big why to remove, because your 20+ year old heat cycled old tvis butterfly has been known to fail at high boost - pieces flying into your intake valves.
No later gen has TVIS, however does have a port design change to the head. TViS remove.

Torque dip is another aspect - give it to your tuner. Camshaft dialing, rpm boost control (run an extra 2psi at a particular rpm range to smooth out aspects) and other things are done to smooth the tune, just know the more focused on the tune, the more the cost.

Costs money to make hp - ATS spacer.

1% mod guide - Cheap mans guide to tvis mod (when making big hp);

Little home multi-sander-trimmer tool with metal blade, can cut the butterfly and port divider.
Wield the holes (take to a welding shop), stick weilder won’t work on the metal, experience of it cracking off when welded at guys home welders - get a professional to weld it for cheap and piece of mind.
Then gasket port match the manifold, and tvis spacer. Porting tvis and intake runner where connects to tvis, use a standard dremel high speed cutter finish or rough sand paper. Do not polish.
Your head needs to be off the engine to port, or risk of fine metal fragments in your engine, best advice don’t port the head unless it’s your day job and off the engine.
That’s the cheap tvis mod. By the time you add up the cutter, blade, dremel, attachments, welding, hours of time - it’s still a decent cost. After helping guys do this mod, I don’t anymore because I don’t have a full spare day. I have and will recommend the ATS spacer.

IMO - If heads off and have time (oh I miss those days) - gasket match intake with rough finish, polish chamber (with valves in place), polish exhaust gasket match. Gen2 heads flow good volume, you don’t need to change/increase the port shape. Measure measure measure along the process to keep consistencies in what you do to all and do as little as possible. Enjoy :)